Folding wing



Oct. l, 1935.

l. IZSAK El AL.

FOLDING WING Filed Deo. 21, 1952 6 Sheets-Sheet l l. IZSAK El' AL FOLDING WING 6 Sheets-Sheet 2 Filed Deo. 2l, 1932 lee f/ f/ I l l. sa, f f`| l INVENTOR Wl TA/Eff l. IZSAK A ET AL FOLDING WING Oc.. L, 1935.

Filed Dec. 2l, 1932 6 Sheets-Sheet 3 o m w n n w u n L l. IZSAK ET AL Get. 1, 1935.

FOLDING WING Filed Dec. 21, 1932 6 Sheets-Sheet 4 WJZWESSE'S Oct. l, 1935. V l. lzsAK ET AL FOLDING WING Filed Deo. 2l, 1932 6 Sheets-Sheet 5 Saw "T97 JS) WFA/@SSFS Wa@ wa' l. IZSAK ET AL FOLDING WING Oct. l, 1935.

Filed Dec. 2l, 1932 6 Sheets-Sheet 6 MZWEWSE'S fm- Patented Oct. 1, 1935 UNITED STATES PATENT OFFICE 3 Claims. (Cl. 244-12) lo a novel folding wing construction having hinged and sliding means for the struts to permit the of Figure 6. easy folding of the wings. Figure 8 is a fragmentary top elevational view A still further object of the invention is to proof a folding wing ready to be locked, full lines vide anovel folding Wing construction to permit indicating when in flight, and dotted lines india reduced storage space for the airplane in the cating when wing is folded rearward alongside l5 hangar. the fuselage.

A still further object of the invention is to pro- Figure 9 is an enlarged top plan view and fragvide a novel folding wing construction, which mentary sectional view of the locking means to will be compact, simple, easily assembled and eflisecure the front spar of the wing to the top cient in carrying out the purpose for which it is longeron. 20

designed. Figure 10 is an enlarged top plan view and With the foregoing and other objects in view, fragmentary sectional view of the hinged and rowhich will appear as the description proceeds, tatng means t0 Secure Jthe real Spal' 0f the Wing the invention consists in certain novel features tothe top longeron.

of construction, arrangement, and combination Figure 11 is an enlarged elevational View of the 25 of' parts, hereinafter more fully described, illushinged and pivotal means to secure the lower trated in the accompanying drawings, and parends of the front and rear strut to the bottom ticularly pointed out in the appended claims. longeron.

It is to be understood that various changes in Figure 12 is an enlarged sectional view on line the form, proportion, size and minor details of |2|2 0f Figure 11- 30` the structure may be made without departing Figure 13 is a fragmentary end sectional view from the spirit or sacrificing any of the advan- 011 line |3-l3 0f Figure 12- tages of the invention. Figure 14 is a fragmentary elevational view of For the purpose of facilitating an understandthe hinged means t0 Secure the uppe` end 0f the y ing of our invention we have illustrated in the rear strut to the rear spar. 35

accompanying drawings preferred embodiments Figure 15 is a fragmentary end Sectional view thereof, from an inspection of which, when conon line l5|5 of Figure 14. sidered in connection with the following descrip- Figure 16 is a fragmentary front elevational tion, our invention, its mode of operation, assemview of the hinged and sliding means to permit 40..: bly, and many of its advantages should be readily the upper end of the front strut to slide forward 40.

understood and appreciated. when the wing is folded.

Referring to the drawings, in which similar Figure 17 is a cross sectional view on line Il-Il characters of reference are employed to indicate of Figure 16.

corresponding or similar parts throughout the Figure 18 is a cross sectional view on line i8--l8 several figures in the drawingszof Figure 16. 45

Figure 1 is a top plan view of the framework Figure 19 is an assembled top plan view of the of the folding wing, ready to be locked, the covdisconnecting means and of the locking device to ering being removed in order to show the locksecure the front spar of the wing to the top ing device inside of the Wing. longeron. y

Figure 2 is a cross sectional view of the frame- Figure 20 is an end cross sectional view on line 50 work of the folding wing taken approximately on 2li- 20 of Figure 19. the line 2--2 of Fig. 1, showing the locking mech- Figure 21 is a fragmentary cross sectional top anism inside of the Wing structure. view on line 2 I-2I of Figure 20.

Figure 3 is a fragmentary front elevational Figure 22 is an assembled end elevational view view of the folding wing construction. of the locking device inside of the Wing structure. 55

The invention relates to improvements in folding wings, in association with an airplane.

The main object of the invention is to provide a novel folding wing construction having hinged and rotating means to fold the Wings.

Another object of the invention is to provide a novel folding Wing construction having locking means to secure safety for the Wings, when flying.

A further object of the invention is to provide Figure 4 is an assembled elevational view of the control wheel to manipulate the cables to effect the folding of the Wing.

Figure 5 is a fragmentary sectional view of the grooved portion of the control wheel on the line 6 5-5 of Figure 4.

Figure 6 is an assembled elevational view of the disconnecting means of the cables leading to the ailerons on the line 6-6 of Figure 1.

Figure 'l is a top sectional view on the line 'l--l l0 The drawings refer only to the right hand wing. The left hand wing is not shown. Its folding operation is identical to the right hand wing.

Referring to the drawings more specifically, I denotes the right hand top longeron of a fuselage, 2 the framework of a wing of standard construction, 3 the ribs of the wing, 4 the front spar of the wing, 5 the rear spar of the wing, 6 the front strut, 1 the rear strut.

The rear spar 5, is covered with a sheet steel ferrule 26, at its inner end and is made fast by bolts 2|, and nuts 22. The rear spar 5, is cut out at its inner end for the receipt of the offset portion 23, threaded projection 24, safety nut 25, and cotter pin 26, of the hinge |13 projecting through a hole drilled at the center of the back wall of the ferrule 2D, to provide a rotatable mounting of the rear spar 5, on the offset portion 23. This forms the wing half of the connecting hinge.

The eye of hinge I 13 is fastened to the fuselage hinge member |14 by means of the eyebolt 21, and safety nut 33. 'I'he fuselage hinge member |14 is brazed to the fitting 28, is wrapped around the vertical fuselage strut and is made secure by the tightening of the tension bolts 3|, passing through its fianges 39 30, by the nuts 32. This forms the fuselage half of the connecting hinge (Figure The front spar 4, is covered with a steel forging tting I3, at its inner end very carefully machined and reduced in weight, and is made fast by bolts I4, and nuts I5. Fitting I3, has a T-shaped projection I6, at its front end. The web part of the T-shaped projection |5, is provided with a drilled hole I9, and at its bottom with the flange I1. This forms the wing half of the locking means.

The T-shaped projection I6, of the fitting I3, ts into the inside of the housing I2, a steel forging very carefully machined. The housing |2, is brazed to fitting 8, is wrapped around the top longeron I, and the vertical fuselage strut (S) and is made secure by tightening of the tension bolts I0, passing through flanges 9 9, by nuts II.

The side anges 29 29, of the housing I2, are provided with the holes I8 I8, in line with the hole I9, of the web of the T-shaped projection I5, to facilitate the locking of the wing. This forms the fuselage half of the locking means (Figure 9).

The rear strut 1 is covered with a sheet steel ferrule 36, at its lower end, and is made fast by bolts 34, and nuts 35. The ferrule 36, has a projection 31, terminating in a horizontal part 38, provided with a hole to permit the passage of the pivot bolt 4 I, held in position by the nut 85.

The front 6, is covered with a sheet steel ferrule 39, at its lower end, and is made fast by the bolts 83, and the nuts 84.

The ferrule 39, has a forked projection 46, at a suitable oblique angle, provided with holes to permit the passage of the bolt 52, held in position by the nut 53.

The bracket 53, has a flange 42, at a suitable oblique angle, conforming to the angle of the forked projection 40. The flange 42, ts between the sides of the forked projection 40, and is provided with a hole in line with the holes in the sides of forked projection 4l), to permit the passage of the hinge bolt 52.

The bracket 43, has another projection 44, conforming to the shape of the projection 31, and the horizontal part 38, of the ferrule 36, and are joined together by the rivet |65. This forms the struts half of the connecting hinge.

The clevis 45, is brazecl to the fitting 46, is

passed around the bottom longeron 41, and is wrapped around the vertical fuselage strut 48, and is made secure by tightening the tension bolts 50, passing through its flanges 49 49, by nuts 5|. The flanges |4| |4|, and the tension bolts |54 are provided for the attachment of the fitting of the chassis strut. This forms the fuselage half of the connecting hinge (Fig. 11, and Fig. 12).

The rear strut 1, is covered with a steel forged fitting 54, at its upper end, and is made fast by 10 bolts 64, and nuts 65. The fitting 54, has an upturned projection 55, with a hole in its end. Projection 55, is hinged between the forked part of 56 56, of the bracket 51, by means of bolt 60, and nut 6|. Bracket 51, passes around the rear 15 spar 5, and is made fast by the bolts 58, and the nuts 59 (Fig. 14, and Fig. 15)

The front strut 6, is covered with a steel forged fitting 62, at its upper end, and is made fast by the bolts 66, and the nuts 61.

The fitting 62, has a twisted and upturned forked projection 63, with holes provided for the receipt of bushing 69. One end of the arm 68, is mounted on the bushing 69, between the forked part of projection 63. The rounded end of the arm 68, fits between the recess of the sliding carriage 1B, and is held in place by the bolt 1|, and nut 14.

The sliding carriage 1U, by means of its top flange 12, is able to slide on the inside lower anges of an inverted track 13, which has an opening at its bottom, to permit the unobstructed sliding of the web part of the carriage 10. The inverted track 13, has a slightly inclined part with enlarged depth a-t its inner end to facilitate an easy start for the carriage 16, when the wing has to be folded.

The track 13, is secured to the bottom part of the front spar 4, by the screws |16.

The carriage 10, has an eyelet at its inner end, to attach the cable 14, guided in the groove 15, of the arm 68, and leading through the guide sheaves |24, and |25 respectively, to the groove |20, of the control wheel IIB, being securely fas-tened to it at a suitable place.

The bottom flange 93, of a suitable bracket 92, is fastened at a convenient place to the upper part of the bottom of the rib 3, nearest to the fuselage, by means of Ithe screws |53 |53.

The top flange 9|, of the bracket 92, supports 50 the equalizer 96, by means of a double wedged shaped conical pin 86, which has a bottom flange 81, resting on the top of the equalizer 90, a threaded projection 89, with a square portion 88, that fits into the square hole of the equalizer 55 90, located at its center.

The projection 89, passes through the hole of the top flange 9|, and is rotatably retained by the nut |58. The equalizer 9|), has eyelets at its ends to attach the cables 99 99, leading to the 60 equalizer |69, inside of the wing structure. This forms the wing half of the disconnecting means of the outer locking mechanism.

The conical pin 86, fits in side of the housing 8|, open at its bottom. Housing 86, has a top fiange 82, a threaded projection 83, with a square portion 80. The lever 15, has the knob 16, at one end, and a square hole at its other end, that fits over Ithe square portion 86, of projection 89. The operating lever 15 is rotatably 70 retained between the flange 82, and the horizontal flange of the bracket 85, by the nut 68. The bracket 85, is secured to the top longeron by screws |56.

The spring lever 11, is secured to the top of the operating lever 15, by means -of the rivets 18. The plunger 19, is secured at a suitable place to the spring lever 11, by the nut |62, and projects in the hole |10, and |1I respectively of the plate |12.

The connecting rod 94, is secured at one end to -the lower projection |61 of the knob 16, by the nut |63. At its other end it is secured to the lock pin 95, by the screw 96.

The lock pin 95, has a round projection 91, which guides the pin during the locking of the wing. The projection 91, is supported in the flange 98, of the bracket |54, made fast to the top longeron I, by means of screws |65.

The plate |12 is fastened at a suitable place to the bottom part of the top longeron I, by means of the screws |69, and is provided with two holes |13 and |14 suitably located to accommodate the plunger 19, in its locking and unlocking position. This forms the fuselage half of the disconnecting means and the outer locking mechanism (Fig. 2l, Fig. 23, Fig. 24.)

The equalizer |00, has eyelets at its ends to attach the cables 99 99, leading from the equalizer 90. It is mounted at a suitable place on the plate |0I, secured in the recess of the tie board |02, made fast to the upper parts of the bottoms of two adjacent ribs ||5, |51.

Equalizer |00, is pivotally mounted on the bolt |03, and held in place by the nut |04.

Equalizer |00, has a projection |05, at its outer end which is connected to a bent connecting rod |06, by means of the bol-t |01, and the nut |08. The other end of the connecting rod |06, is se cured to the lock pin |09, by the screw I|0. The lock pin |09, fits the inside of the bushing 69.

The lock pin |09, has a round projection is guided in the flange ||2, of the bracket II 3, screwed to the bottom of the rib I I 5, by the bolts H6, and the nuts |I1. This forms the locking mechanism inside of the wing structure 2 (Fig. 22).

The folding wheel I I8, is provided with grooves ||9, and |20, for the reception and to secure the cables 14, and |2|, respectively, performing the folding of the wing.

The cable 14, leads by means of the guide sheaves |24, and |25, to the eyelet of the sliding carriage 10, of the front strut 6.

The cable |2|, leads by means of guide sheave |23, suitably located at the tail end of the fuselage, to the attachment |22, of the rear strut 1.

The folding wheel ||8, 1s supported by the brackets |26, secured to a vertical member of the fuselage |52 and to a horizontal member of the fuselage |53, at suitable places by the bolts |21. The bent operating lever |28, is fastened to the outside flange |54, of the folding wheel ||8, by the countersunk bolts |29, and the nuts |30.

The knob |3|, is secured to the top projection of the lever |28, to rotate the wheel.

The operating lever |28, is pivotally mounted on the pin |34, secured in the plate |32, fastened to the vertical member |52, and the horizontal member |53, `of the fuselage by wood screws |33.

The operating lever is retained on the pin |34, by the washer |35, and the nut |36 (Fig. 4 and Fig. 5).

The bottom ange |50, of a suitable bracket |49, is fastened at a convenient place to -the upper part of the bottom of the rib 3, nearest to the fuselage by means of screws |5I, |5|. The top iiange |48, of the bracket |49, supports the equalizer |31, by means of a double wedged shaped conical pin |45, which has a bottom flange |46, resting on top of the equalizer |31, a round threaded projection I 41, with a square portion |38, that fits into the square hole of the equalizer |31, located at its center. The projection 5 |41, passes through the hole of the top ange |48, and is rotatably retained by the nut |51.

The equalizer |31, has eyelets at its ends to attach the cables |59 |59, leading to the ailerons. This forms the wing half of the disconnecting means of the ailerons.

The double wedged shaped conical pin |45, ts inside the housing |39, open at its bottom. The housing |39, has a top flange |40, and a round threaded projection |4I, with a square portion |60.

The arm |6I, has a square hole at one of its ends, that iits over the square portion |60. The arm is rotatably retained between the top ange |40, and the horizontal flange |58, of the bracket 20 |42, by the nut |44. 'Ihe bracket |42, is made fast at a suitable place to the side of the top longeron I, by means of the screws |43 |43. The arm I6 has two eyelets at its other end to attach the cables leading to the control sticks. This forms the fuselage half of the disconnecting means of the ailerons (Fig. 6 and Fig. '7)

How the folding of the wings is accomplished:

When the machine has to be shipped, or removed to the hangar after a flight, the pilot with one of his fingers lifts the spring 11, by means of the plunger 19, from the hole I 1|, of the plate |12. Taking hold of the knob 16, with his other finger, the operating lever 15, is rotated to the right, until the plunger 19, enters the hole |10 of the plate |12. During the rotation the connecting rod 94, withdraws the lock pin 95, from the hole I9, of the web of the T- shaped projection of the fitting I3. Simultaneously the operating lever 15, rotates the housing 8|, by bearing on its square portion 80. Housing 8 in turn rotates the double wedged shaped conical pin 86, which by its square portion 88, is oscillating the equalizer 90. The latter, by the cables 99 99, produces harmonious oscillations in the equalizer |00, inside of the wing structure, and its projection |05, actuates the bent connecting rod |06, and the latter withdraws the lock pin |09, from within the bushing 69, to such an extent to free the arm 68, and permit the sliding of the upper part of the front strut 6.

When the lock pins 95, and |09, respectively, are withdrawn, the pilot manipulates the folding wheel I|8, located in the cock pit by gripping the knob |3|, of the lever |28. By rotating the 55 folding wheel ||8, clockwise, a pull is produced in the cable |2|, compelling the rear strut 1, to rotate on the pivot 4|. A corresponding slack in the cable 14, leading to the eyelet of the sliding carriage of 10, of the front strut 6, is enabling the latter to slide forward in the inverted track 13.

The wing begins to rotate downward on the offset portion 23, of the hinge |13.

The T-shaped projection I6, of the fitting I3, gradually slides out from within the housing I2. The double wedged shaped conical pins 86, and |45, slide out from within the housings 8|, and |39. This accomplished the wing starts to fold rearward on the hinges of |13 and |14.

The particularly constructed hinged and pivotal arrangements of the fittings, covering the upper and lower ends of the front strut 0, and the rear strut 1, as set forth, permit the gradual folding of the wing alongside the fuselage.

In case the wing has to be made ready for 75 flying, the folding wheel H8, is rotated anticlockwise. A pull will be produced in the cable 14, which gradually rotates the wing upward on the offset portion 23, of the hinge |13, until the sliding carriage 1li, is brought back to its original position. The corresponding slack in the cable |2I, is enabling the wing structure to reach its flying position. The double wedged shaped conical pins 86, and |45, re-enter gradually the housings 8|, and |39. The T-shaped projection |6, of the fitting I3, re-enters the inside of the housing |2, and when its bottom flange I1, touches the sides 29 29, of the housing |2, the wing is ready to be locked.

By lifting the spring 11, the plunger 19 is removed from within the hole |10, of the plate |12. The operating lever 15, is moved backward to the left, until the plunger 19, enters the hole |1|, of the plate |12. Simultaneously the operating lever 15, moves forward the connecting rod 94, which pushes the lock pin 95, into the holes |1, of the web of the T-shaped projection I6, and into the hole I8, of the outer side 29, of the housing |2, locking them securely together.

The movement of the operating lever 15, furthermore oscillates the equalizer 90, as set forth, which in turn harmoniously oscillates equalizer |00, inside of the wing structure, and its projection |05, moves forward the bent connecting rod |06, which pushes the lock pin |99, within the bushing 69, to such an extent, that it locks the forked projection 63, of the tting 62, covering the upper end of the front strut 6, to the front part of the arm 68, supported by the front spar 4, of the wing structure 2, making the wing safe for flying.

The exposed part of the locking device inside of the wing can be covered in stream line fashion.

The gap between the inner end of the wings and the outside face of the fuslage can be covered with thin sheeting airfoil shape.

What we claim as new and seek to secure by Letters Patent is:

1. In an airplane having folding wngs, a combination of wing supporting front and rear spars and struts, equipped with means, whereby the wings may be rigidly connected to the fuselage; said front spars having at their inner ends means for disconnecting the inner front portions of the wings from the fuselage, said front struts having at their outer ends means to unlock the rigid connections between the front struts and the outer front portions of the wings,

said rear spars and rear struts having at their 5 inner ends means that permit the disconnected Wings to rotate backwards, said inner ends of the rear spars terminating in pivots which in combination with the pivotal connections of the rear struts and rear spars permit horizontal rol0 tations of the said disconnected portion of the wings; all of which operations are controlled by suitable means from within the fuselage.

2. In an airplane having folding wings, a combination of wing supporting front and rear spars 15 and struts, equipped with means, whereby the wings may be rigidly connected to the fuselage; said means comprising locking and unlocking devices disposed between the inner ends of the front spars and the fuselage and between the 20 outer ends of the front struts and the outer front portions of the wings; vertical hinges disposed below between the fuselage and the rear struts and above between the fuselage and the inner ends of the rear spars; pivotal connections be- 25 tween the rear struts and the rear spars which in combination with the hinges of the rear spars permit backward and forward rotation of the disconnected wings; the locking and unlocking devices being operated by lever movements while 30 the rotations are produced by means of grooved folding wheels guiding the control cables, all of which operations are performed within the fuselage.

3. An airplane having a fuselage and folding 35 wings attached thereto, said wings having front and rear spars interconnected by transverse ribs, supporting struts for said wings, means to disconnect the wings from the fuselage; said means comprised of upper and lower halves, disposed 40 between the inner ribs and the fuselage; the upper halves of which are shaped as receptacles supported at the sides of the fuselage, while the lower halves are shaped as double wedged conical pins fitting within said receptacles fastened 45 to the bottom portions of the inner ribs and lever elements disposed within the fuselage for operating said means.

IGNACIO IZSAK. VINCENT BUKLETISH. 50 

